Door closer brake



B. A. QUINN DOOR CLOSER BRAKE Filed Oct. 9, 1965 Dec. l, 1964 INVENTOR. BERT A. CDU/NN N .QE

ATTQRNEv/s United States Patent O 3,158,894 D993 CLIESER BRAKE Bert A. Quinn, St. Paul, Minn., assigner to ideal Erase Works, Incorporated, St. Pani, Minn., a corporation of Minnesota Filed 9ct, 9, 1h63, Ser. No. 3714,93@ 2 Ciairns. (Cl. Ele-66) My invention relates generally to automatic doorclosing mechanisms, and more particularly to springactuated door-closing devices which rely upon pneumatic pressures to counteract the action of the springs, whereby to impart orderly closing movements to the door.

Devices of the class above described normally include an elongated cylindrical casing in which is mounted a plunger-equipped piston, one end of the casing being securable to a door, and the extended end of the plunger to the door frame, or vice-versa.

Under unusual conditions, due to strong gusts of wind and the like, doors equipped with such devices are known to be thrown open against the action of the springs with such force as to damage both the door and the closure mechanism. To offset this, braking means have heretofore been provided for automatically checking such undesirable door-opening movements. However, such known means take effect progressively as the piston moves from one end of the cylinder toward the other end thereof. Consequently, one manually opening a door so equipped is required to exert additional and objectionable door-opening force thereagainst, even during initial opening movements.

The primary object of my invention is the provision of a novel brale'ng mechanism which will not go into effect during the initial opening movements of the door so as to avoid any objectionable drag during normal manual door-opening movements. Under auch an arrangement the automatic braking mechanism does not go into play until the latter Apart of the stroke of the piston in its rtravel from one end of the cylindrical casing to the other end thereof.

A further and highly important object of my invention is the provision of a device of the class described wherein the door is prevented from starting to close -too fast, whereby to bring about `a smoothness of closing action without over compressing the air within the cylinder to cause a rebound.

A still further object of my invention is the provision of a device of the class immediately above described wherein there is no loss of closing power as lthe door approaches latching position.

A further object of my invention is the provision of a device of the class above described ywhich is inexpensive to produce, which incorporates a minimum of working parts, and which is positive and foolproof in its operation.

The above and still further objects of my invention will become apparent from the following detailed specification, appended claims, and attached drawings.

Referring to the drawings wherein like characters indicate like parts throughout the several views:

FIG. l is a view in horizontal section through a door casing and a door mounted therein showing my novel closure device in plan;

FIG. 2 is a view in axial section as seen from the line 2 2 of FlG. 1 on an enlarged scale;

FIG. 3 is a greatly enlarged view in axial section of a portion of the structure shown in PEG. 2, showing a different position of parts thereof;

FlG. 4 is an enlarged view in perspective of the brake shoe utilized in the structure of FIG. 2, portions thereof broken away; and

FlG. 5 is a View similar to FIG. 3, showing a modilied embodiment.

Fice

Referring with greater particularity to the drawings, and initially to the preferred embodiment of FIGS. l to 4, inclusive, the elongated cylindrical casing of my novel door closer is identified by 10. Mounted for axial sliding movements within the casing 10, in sliding engagement with the inner side wall 11 thereof, is a piston identied in its entirety by 12 and, as shown, comprising primary and secondary piston sections 12a and 12b. Extending loosely through piston section 12b and fast on the `axis of section 12a is a plunger rod 13, the outer end 14 of which projects loosely through an opening 15 in one end i6 of the casing 1G. At its projected free end the plunger 13 is provided with suitable bracket means i7 for securing same to a door frame A; whereas the other end 1d of the casing 1t) is provided with suitable racket means 19 for securing same -to the screen or storm door B.

Piston section 12a, as shown, is preferably formed from a pair of cooperating annular disks 20, 21 of specifically different cross sectional contour, and secured together at their radially inner limits and made fast on the inner end 13a of the plunger 13 by peening over the reduced end of the latter, as indicated `at 22.

At their 'radially outer ends, the disk-like portions 2b, 21 cooperate to deiine ya radially outwardly opening annular groove 23 in which is received for limited axial sliding movements, while in engagement with the inner wall surface 11 of the casing 19, an O-ring 24. It will be noted that during axial movements of the piston 12 from the end 13 of the casing 1t) toward the end 16 thereof that the O-ring 24 will be removed from engagement with a cam surface 25, defined by element 21, whereby to permit air freely to pass thereunder and outwardly through the port 26 in the element 2l?, see particularly FIG. 3. Gn the other hand, when 'the piston 12 is moved axially from the end 16 of the casing 10 toward the end 18 thereof, the O-ring 24 is forced to climb up upon the cam ring surface 25 and make sealing engagement with the inner wall 11 and the casing 10.

Because the element 21 or" the piston section 12a and piston section 12b are formed from sheet metal stampings, same are separately formed. However, in the operation of my device, l wish it to be specifically understood that these parts `could well be integrally formed. In Iany event, a coil compression spring 26a loosely encompasses the inner end 13a of the plunger -rod 13 with one end thereof in abutting relationship to the piston 12, as indicated at 27, and with the other end received in a counterbore 2S formed in a collar 29 slidably received on said plunger rod 13.

As shown particularly in FIG. 3, the collar 29 Vat its periphery is formed to define an annular cam surface 30 which tapers in the direction of the piston section 12b; whereas the piston section 12b is formed to define an annular cam surface 31 which tapers in the direction of the collar 29. interposed between the cam surfaces 30, 31 of the collar 29 yand piston section 12b, respectively, is an annular brake shoe 32, yaxially split as at 33 and having axially spaced converging cam surfaces 34, 35 which cooperate respectively with the cam surfaces 36, 31 when yielding bias is exerted upon the collar 29 by a coil compression spring 36 with suicient force to overcome the compression value of coil compression spring 25. As shown, the coil compression spring 36 also encompasses the plunger rod 13 and has one end in abutting relationship with the collar 29 within Ian annual recess 37 and the other end in engagement with the restricted end 16 ofthe casing ll).

With the novel combination and arrangement of parts immediately above described, the coil compression spring 36, because of its length, normally biases the piston 12 and parts carried thereby toward end 18 of casing 10,

Ydoor B, under conditions above described.

as shown in FIG. 2. However, because of the yrelative compressive values of the springs 36 and 26 when in said position, the piston element 12b becomes separated from the section 12a and exerts no braking pressure against the brake shoe 32. It might here be stated that during movements of the piston 12from the end 16 toward the end 18 of the casing 16 that air is permitted to escape as desired'from the end 18 through the medium of an adjustable valve, shownY as being in the nature of a conventional vented screw 3S.

When opening movements are imparted Ito the door B against the yielding bias of coil compression spring 36, the yielding bias of the coil spring 26 is progressively overcome during initial `movements of the piston i2. However, at this point, and after a given distance of travel ofvthe piston 12, determined solely by the Irelative lengthand values of the springs 26, 36, the two sections 12a, 12b of the piston 12 will come together and the cam surfaces 30, 31 of the collar 29 and piston 12 come into operative engagement with the respective cam surfaces 34, 35 of fthe brake shoe 32 and start to progressively exert greater radially outward `braking pressure upon the cylindrical wall 11 of the casing 10. Such braking pressure stops movement of the piston 12 suiciently in advance of the inner end 16 of the casing, or alternatively slows down the speed of piston 12, to prevent damage to either rthe door B or of my novel door-closing mechanism above described, during uncontrolled 'opening movements of In the slightly modified structure of FIG. 5, wherein parts similar to the structure of FIGS. 1 to 4, inclusive, are similarly identiiied, the piston section 12C is shown VVas beingin the nature of an annular washer, interposed between section 12a and the collar 29. Consequently, the brake shoe 32a is provided Vmerely with one cam surface 34a, which is adapted to cooperate with the cam surface 30 of the collar 29. The operation of this structure is obviously identical to that of Vthe structure 'FGS 1 to 4, inclusive. Y

My invention has been thoroughly tested and found to be entirely satisfactory for the accomplishment of the above objects; and while I have disclosed a preferred embodiment thereof, my invention may be capable of modiiication without departure from the scope and spirit of the appended claims.

What is claimed is:

1. In a pneumatic door closer:

(a) an elongated cylindrical casing, p

(b) a piston slidably received within said casing and having any axially vextended plunger rod projecting through one end thereof,

(c) said piston and the opposite end of said casing cooperating to denne check valve means for regulating the rate of movement of said piston toward Said opposite end of saidrcasing, and

(d) means for progressively applying braking action to said piston as same moves from said other end of said casing to said one end thereof, said means comprising:

(l) a collar slidably received on said plunger rod within said casing and' defining a cam acting surface which tapersV toward said opposite end of said casing,

(2) a coil compression spring encompassing said plunger and interposed between said piston and said collar and yieldingly biasing same apart,

(3) a second coil compression spring encompassing said plunger rod vwithin said casing and interposed between said collar and said one end thereof and having a greater compression value than that of said rst mentioned compression spring, and Y (4) an axially split annular brake shoe interposed between said piston and said collar and having a tapered cam `acting surface on one side which cooperates with the reversely tapered cam acting surface on said collar, whereby to cause said brake shoe to engage the inner wall of said casing with progressively increasing braking pressure as said second mentioned spring progressively overcomesrthe force exerted by said rst mentioned spring during movements of said piston from said opposite end of said casing toward said one end thereof,

(5) the relative length and compression values of said compression springs coupled with the dimensions of said brake shoe being such las to delay the expanding braking pressure exerted by said collar upon said brake shoeduring initial movements of said piston fromv said opposite end to said one end of said casing.

2. The structure defined in claim l in which said piston defines a second 0am acting surface which tapers toward said one end of said kcasing :and in which said brake shoe is also formed to define a reversely tapered cam acting surface which cooperates with said second lcam acting sur-face on said piston to expand said brake shoe during said movements.

References Cited by the Examiner UNITED STATES PATENTS DONLEY I. STOCKING, Primary Examiner. 

1. IN A PNEUMATIC DOOR CLOSER: (A) AN ELONGATED CYLINDRICAL CASING, (B) A PISTON SLIDABLY RECEIVED WITHIN SAID CASING AND HAVING AN AXIALLY EXTENDED PLUNGER ROD PROJECTING THROUGH ONE END THEREOF, (C) SAID PISTON AND THE OPPOSITE END OF SAID CASING COOPERATING TO DEFINE CHECK VALVE MEANS FOR REGULATING THE RATE OF MOVEMENT OF SAID PISTON TOWARD SAID OPPOSITE END OF SAID CASING, AND (D) MEANS FOR PROGRESSIVELY APPLYING BRAKING ACTION TO SAID PISTON AS SAME MOVES FROM SAID OTHER END OF SAID CASING TO SAID ONE END THEREOF, SAID MEANS COMPRISING: (1) A COLLAR SLIDABLY RECEIVED ON SAID PLUNGER ROD WITHIN SAID CASING AND DEFINING A CAM ACTING SURFACE WHICH TAPERS TOWARD SAID OPPOSITE END OF SAID CASING, (2) A COIL COMPRESSION SPRING ENCOMPASSING SAID PLUNGER AND INTERPOSED BETWEEN SAID PISTON AND SAID COLLAR AND YIELDINGLY BIASING SAME APART, (3) A SECOND COIL COMPRESSION SPRING ENCOMPASSING SAID PLUNGER ROD WITHIN SAID CASING AND INTERPOSED BETWEEN SAID COLLAR AND SAID ONE END THEREOF AND HAVING A GREATER COMPRESSION VALUE THAN THAT OF SAID FIRST MENTIONED COMPRESSION SPRING, AND (4) AN AXIALLY SPLIT ANNULAR BRAKE SHOE INTERPOSED BETWEEN SAID PISTON AND SAID COLLAR AND HAVING A TAPERED CAM ACTING SURFACE ON ONE SIDE WHICH COOPERATES WITH THE REVERSELY TAPERED CAM ACTING SURFACE ON SAID COLLAR, WHEREBY TO CAUSE SAID BRAKE SHOE TO ENGAGE THE INNER WALL OF SAID CASING WITH PROGRESSIVELY INCREASING BRAKING PRESSURE AS SAID SECOND MENTIONED SPRING PROGRESSIVELY OVERCOMES THE FORCE EXERTED BY SAID FIRST MENTIONED SPRING DURING MOVEMENTS OF SAID PISTON FROM SAID OPPOSITE END OF SAID CASING TOWARD SAID ONE END THEREOF, (5) THE RELATIVE LENGTH AND COMPRESSION VALUES OF SAID COMPRESSION SPRINGS COUPLED WITH THE DIMENSIONS OF SAID BRAKE SHOE BEING SUCH AS TO DELAY THE EXPANDING BRAKING PRESSURE EXERTED BY SAID COLLAR UPON SAID BRAKE SHOE DURING INITIAL MOVEMENTS OF SAID PISTON FROM SAID OPPOSITE END TO SAID ONE END OF SAID CASING. 